1. Field of the Invention
The present invention relates to a noise reduction nacelle for jet aircraft for absorbing high frequency harmonics produced by the high speed air flow exhausted from the primary fan nozzles and by dampening noise generated by fan air and rotating stages of the engine wherein the noise reduction is accomplished by installation of an acoustically treated engine inlet, center body and bifurcated duct.
2. Description of the Backqround
The existing nacelles for various types of jet aircraft is exemplified by FIG. 1 which serves to illustrate a nacelle 1, an engine inlet duct 2, a center body 4 and a fan-exhaust duct 6. An engine of this type typically includes a fan-exhaust thrust reverser 8 shown in a stowed position or can be operated to provide a fan-exhaust thrust reverser 10 in an extended position. Aircraft of this type have difficulty in complying with current noise restrictions and it has therefore become important that noise reduction for compliance with Federal regulations be provided without requiring significant engine modifications and while maintaining the economy and profitability of the aircraft itself. More particularly, it is important that no modifications be required to the engine nacelle cowling. In addition, the pan panels and venetian blinds should remain as originally manufactured and there should be no required changes to the cascade and aft reversers. In addition, the inlet cowl and bullet (i.e. center body 4) should be where possible identical in size to the original equipment.